The present invention relates to a gathering stapler for printed products, namely folded printed sheets.
Gathering staplers are known in the art. The nature and operating principle of rotary stapling devices has long been known to persons skilled in the art. Rotating stapling heads commonly include a push rod for driving in the staples. The displaceable push rod is guided in the radial direction. Prior art examples of such gathering staplers include the arrangement disclosed in U.S. Pat. No. 4,408,755 and the corresponding Swiss Patent No. 645,074. These references teach a gathering stapler capable of gathering printed sheets, which are initially still joined together in the form of folded webs, without the usual opening devices. The gathered printed sheets gathered are then stapled in the stapling region of the circulating rests by a rotary stapling apparatus.
In prior art gathering stapler devices, the push rod is constantly changing its angular position during the driving in of the staples. Usually, the push rod and rest, which supports the product to be stapled, are aligned only in a single rotational position. Despite this arrangement, rotary stapling devices are used not only in the above mentioned context, but also in a wide variety of fields.
Therefore, it is an object of the present invention to provide a rotary gathering stapler in which the stapling heads and the rests are aligned with each other over an entire rotational region. Alignment over an entire rotational region would increase the operational reliability, even at an elevated rotational speed. Furthermore, it would be possible to work with different qualities of wire and/or lengths of wire and correspondingly different staple dimensions with minimal setting work.